A cloud service can refer to a service that includes infrastructure resources (a compute resource, a storage resource, a networking resource, etc.) connected with each other and/or platforms. Such infrastructure resources can collectively be referred to as “cloud resources.” A host (also referred to as a cloud service provider) may, as examples, provide Software as a Service (SaaS) by hosting applications or other machine-readable instructions; Infrastructure as a Service (IaaS) by hosting equipment (servers, storage components, network components, etc.); or a Platform as a Service (PaaS) by hosting a computing platform (operating system, hardware, storage, and so forth).
A public cloud is a place where IaaS or PaaS is offered by a cloud service provider. The services of the public cloud can be used to deploy applications. In other examples, a public cloud can also offer SaaS, such as in examples where the public cloud offers the SaaS as a utility (e.g. according to a subscription or pay as you go model).
In other examples, an IaaS can be deployed on premises of a customer, such as the customer's data center. Such an arrangement is referred to as a private cloud. A managed cloud is a private cloud that is managed by a third party or hosted and managed by a third party (if the private cloud is managed by a third party, then the managed cloud is referred to as a virtual private cloud).
In further examples, IaaS can be provided by traditional servers or data centers.
In other cases, a cloud used by a project or a customer can be a combination of all the above (e.g. applications have pieces in different cloud deployments or applications can be moved to different clouds or deployment models). Such a cloud is referred to as a hybrid cloud.
Application stacks (including a platform and operating system as well as other layers) in a cloud infrastructure can also be considered as cloud services. They may be “used” or offered as a service.